Research On Multiple Injection Controller Of High-Pressure Common Rail Diesel Engine

Diesel engine get a wide range of applications for its strong powers and good economic performance. With increasingly stringent emission regulations, the diesel engine to expand the application is blocked. High-pressure common-rail injection technology is recognized as the best solution by insiders. For research and design to make the high-pressure common-rail diesel engine achieve multiple-injection, control system is very necessary.Based on the structure and working principle of the injector which multiple injection common rail diesel engine.Using AMEsim to simulation on the injector,the simulation results show that as the diameter of the hole increases, the needle response speed increases, the injection rate curve rise time of the injector also sooner; Into the hole diameter increases, the more the needle valve lift moments later, but the moment they close sooner; Control chamber volume is too small will cause the needle to lift moment too soon, the volume too large, the system response is too slow.Changes in diameter of the in or out hole and the volume of control chamber which has a great influence on the fuel injection end timing and the fuel injection rate on the final.Through in-depth analysis electronic control system components and control theory of the high-pressure common-rail diesel engine,this paper developed overall control scheme of electronic control system of the high-pressure common-rail diesel engine.Optional Freescale16-bit microcontroller MC9S12XS128as the master chip, according to the needs of the peripheral device interface, design the system circuit of the smallest single-chip, the signal processing circuits the drive circuit of the solenoid valve、the circuit of CAN communications and power management. On the software side, through in-depth analysis of the actual use of the engine, the engine is divided into several different conditions and different combinations of multiple injection, for different conditions and jet combination, the different control strategies is designed and compiled using C language. Through the modular programming, completion of initialization of each module procedure,application of program scheduling and various functional modules.On the homemade device "engine control system integrated test bed" for the part of the simulation experiment, including the collection and processing of signals from various quarters, drive capability of injector test, carry different combinations of multiple injection conversion depending on the speed and injection timing, etc. Through simulation experiments to know,12V input voltage rises to be stable around80V after the processing by the boost module, and under high pressure driving the injector, the solenoid valve response time is reduced to about2ms, this time is sufficient for the multi injection conditions of the injector. The engine controller can accurately capture the signal, and based on these signals, the control system can take different control strategies. At the different speeds, the engine can achieve to switch different multiple injection combinations. When the engine’s speed is800r/min, the injector perform pilot-main; the speed of1000r/min, the injector perform main-post injection; at1500r/min, the injector perform pilot-main-post injection; the speed of3000r/min, the injector perform main injection. Simulations to verify the hardware system can achieve multiple injection common rail diesel engine electronic control system’s basic functional requirements, underlying driver software’s logic is correct,it can take different control strategies based on signal changes, provides a basic platform for the further study of the performance.Finally, proposed deficiencies and improved methods of research. Further research and made a plan and outlook.